LOL... YES you need alignment after a drop and if you install bags...LOOKOUT!
After installing my bags i had severe toe-out and severe positive camber. It was ridiculous. Then going to 5 local shops and they didn't have scions in their puter. Sears and toyota wouldn't touch it. I was doomed. Finally found a shop who had scions and got it done. Also a word to the wise, If you are sporting low profile tires on large rims (18" & 19") be sure to properly inflate your wheels or it will have an impact on your alignment.